本文選題：CdWO4晶體 + Cd1-xZnxWO4固溶體��； 參考：《寧波大學(xué)》2015年碩士論文

【摘要】：鎢酸鎘(CdWO4)單晶是一種閃爍性能優(yōu)良的閃爍探測(cè)器材料,其X射線吸收系數(shù)大、發(fā)光效率較高,余輝時(shí)間短、抗輻照損傷性能強(qiáng),在核醫(yī)用X-ray CT、集裝箱探測(cè)領(lǐng)域擁有極其重要的應(yīng)用價(jià)值。國(guó)內(nèi)外主要是運(yùn)用提拉法生長(zhǎng)鎢酸鎘晶體,但是提拉法生長(zhǎng)高質(zhì)量鎢酸鎘單晶的主要困難有:熔體揮發(fā)、沿(010)解理面開(kāi)裂、包裹物的產(chǎn)生、晶體著色等。本文主要以鎢酸鎘晶體作為研究對(duì)象,研究工作主要分為以下三部分:1、CdWO4多晶料的固相合成和液相合成。優(yōu)化制備工藝流程,采用固相合成法和液相合成法制備出白色鎢酸鎘多晶料。以液相合成法為重點(diǎn),研究了反應(yīng)溶液pH對(duì)原料純度的影響,探索出滿足晶體生長(zhǎng)用原料的最佳合成條件�？偨Y(jié)了固相合成法和液相合成法合成鎢酸鎘多晶料的優(yōu)缺點(diǎn)。2、CdWO4晶體生長(zhǎng)與性質(zhì)研究。利用液相合成法合成出的高純鎢酸鎘原料,通過(guò)改進(jìn)生長(zhǎng)晶體的溫場(chǎng)、采用提拉法成功生長(zhǎng)出較大尺寸的透明、接近無(wú)色的完整CdWO4單晶。對(duì)單晶的宏觀缺陷及影響晶體生長(zhǎng)的因素進(jìn)行了研究。研究了無(wú)色、透明晶體的腐蝕、透過(guò)光譜、熒光光譜、能量分辨率、絕對(duì)光輸出、熒光衰減時(shí)間性質(zhì)。結(jié)果表明,CdWO4單晶在可見(jiàn)光區(qū)域的透過(guò)率達(dá)70%左右,熒光發(fā)光峰位于473.8 nm,即本征發(fā)光由藍(lán)光組成,能量分辨率為7.8%,絕對(duì)光輸出為20750±375 photons/MeV,CdWO4晶體衰減時(shí)間分別為1329.5 ns和11501.5 ns,與文獻(xiàn)報(bào)道的數(shù)據(jù)進(jìn)行比較、分析,結(jié)果表明采用提拉法成功生長(zhǎng)出高質(zhì)量、高性能的CdWO4單晶。3、Cd1-xZnxWO4固溶體晶體的生長(zhǎng)與性質(zhì)研究。利用高溫固相合成法合成了Cd1-xZnxWO4(x=0,0.1,0.3,0.5,0.7,0.9,1.0)多晶料。粉末X射線衍射分析及結(jié)構(gòu)精修結(jié)果表明,隨著Zn含量的增加,固溶體的衍射峰形從CdWO4的峰形逐漸向ZnWO4的峰形過(guò)渡,晶胞參數(shù)由鎢酸鎘向鎢酸鋅過(guò)渡。通過(guò)優(yōu)化工藝條件,成功生長(zhǎng)出完整、無(wú)宏觀缺陷的Cd1-xZnxWO4(x=0,0.057,0.113,0.416)固溶體單晶。研究了Cd1-xZnxWO4晶體的透過(guò)光譜、熒光光譜、能量分辨率、絕對(duì)光輸出、熒光衰減時(shí)間性質(zhì)。結(jié)果表明,固溶體單晶的吸收邊沒(méi)有變化,在350-600 nm區(qū)域的光透過(guò)率達(dá)65%左右,發(fā)射峰隨Zn含量增加呈現(xiàn)波長(zhǎng)紅移的趨勢(shì)。另外,隨著Zn含量的增加,固溶體晶體的能量分辨率變大、光輸出變小,對(duì)應(yīng)于晶體的衰減時(shí)間的兩個(gè)成分都呈增大的趨勢(shì)。結(jié)合晶體生長(zhǎng)時(shí)熔體的揮發(fā)量,少量摻鋅的Cd1-xZnxWO4(x0.1)晶體是具有高閃爍性能、高生長(zhǎng)特性的閃爍晶體。
[Abstract]:Cadmium tungstate CdWO4) single crystal is a kind of scintillation detector material with good scintillation performance. It has high X-ray absorption coefficient, high luminescence efficiency, short afterglow time and strong radiation damage resistance.Container detection has very important application value in nuclear medical X-ray.Czochralski method is mainly used to grow cadmium tungstate crystal at home and abroad. However, the main difficulties of Czochralski method in growing high quality cadmium tungstate single crystal are: melt volatilization, cracking along the cleavage surface of Czochralski (010), production of encapsulates, crystal coloration, etc.In this paper, cadmium tungstate crystal is taken as the research object. The research work is mainly divided into three parts: solid phase synthesis and liquid phase synthesis of the polycrystalline material: 1: 1 ~ (-1) CdWO4.The white cadmium tungstate polycrystalline material was prepared by solid state synthesis and liquid phase synthesis.The effect of pH on the purity of the raw material was studied with the emphasis on the liquid phase synthesis method, and the optimum synthetic conditions for the raw material for crystal growth were explored.The growth and properties of cadmium tungstate polycrystalline materials synthesized by solid phase synthesis and liquid phase synthesis were summarized.The high purity cadmium tungstate was synthesized by liquid phase synthesis. By improving the temperature field of the crystal, a large size transparent and nearly colorless CdWO4 single crystal was successfully grown by Czochralski method.The macroscopic defects of single crystal and the factors affecting crystal growth were studied.The corrosion, transmission spectrum, fluorescence spectrum, energy resolution, absolute light output and fluorescence decay time of colorless and transparent crystals are studied.The results show that the transmittance of CdWO4 crystal is about 70% in the visible region, and the fluorescence peak is at 473.8 nm, that is, the intrinsic luminescence is composed of blue light.The energy resolution is 7.8 and the absolute light output is 20750 鹵375photons / MeV _ (VN) CdWO4 crystal attenuation time of 1329.5 ns and 11501.5 ns, respectively. Compared with the data reported in the literature, the results show that the Czochralski method has successfully grown high quality.Growth and Properties of High performance CdWO4 single Crystal.CD _ (1-xZn _ XW _ 4) O _ (0. 1) 0. 1 ~ 0. 3 (0. 5) 0. 7 ~ 0. 91.0) polycrystalline material was synthesized by high temperature solid state synthesis.The results of powder X-ray diffraction and structural refinement show that with the increase of Zn content, the diffraction peak of solid solution changes gradually from the peak of CdWO4 to the peak of ZnWO4, and the lattice parameters transition from cadmium tungstate to zinc tungstate.By optimizing the process conditions, the solid solution single crystals of CD _ (1-xZn _ xWO4) O _ (0.057) 0.113 ~ (3) C _ (0.416) have been successfully grown without macroscopical defects.The properties of transmission spectrum, fluorescence spectrum, energy resolution, absolute light output and fluorescence decay time of Cd1-xZnxWO4 crystal are studied.The results show that the absorption edge of the solid solution single crystal does not change and the transmittance reaches about 65% in the region of 350-600 nm. The emission peak shows the trend of wavelength red shift with the increase of Zn content.In addition, with the increase of Zn content, the energy resolution and light output of the solid solution crystal become larger and smaller, and both components corresponding to the decay time of the crystal tend to increase.A small amount of Zn doped CD _ (1-xZn _ xWO4O _ 4) x _ (0.1) crystal is a scintillation crystal with high scintillation property and high growth property combined with the volatile amount of melt during crystal growth.
【學(xué)位授予單位】：寧波大學(xué)
【學(xué)位級(jí)別】：碩士
【學(xué)位授予年份】：2015
【分類號(hào)】：TQ132.44;O78

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